Neurovascular (e.g., cerebral) aneurysms affect about 5% of the population. Aneurysms may be located, for example, along arterial side walls. The aneurysms may have a fundus, a neck, and a fundus-to-neck ratio or “neck ratio.” If the neck ratio is greater than 2 to 1 or if the neck is less than 4 mm, the aneurysm may be treated with embolization coils alone because the coils will generally constrain themselves within the aneurysm without herniating into parent vessels. If the neck ratio is less than 2 to 1 or if the neck is greater than 4 mm, the aneurysms may be difficult to treat with embolization coils alone because the coils may be prone to herniating, or dislodging, into parent vessels. Dislodging of coils may cause arterial occlusion, stroke, and/or death.
In order to inhibit such dislodging, tubular neck remodeling devices may be used to keep coils or other materials within the fundus of the aneurysm and out of the vessels. Tubular remodeling devices generally consist of a braided wire or cut metallic stent or stents covering the neck of the aneurysm so that materials introduced into the fundus of the aneurysm do not herniate out of the aneurysm.
Moreover, occlusion of a blood vessel can be caused by a thrombus (i.e., blood clot) that forms in the blood vessel, or by an embolus, i.e., a blood clot that travels downstream. The blockage disrupts blood flow, which prevents oxygen and nutrients from being delivered to their intended locations. Tissue distal to a blood clot that is deprived of oxygen and nutrients can no longer function properly. For every minute that treatment is delayed, additional cellular death of critical tissue can occur.
Current technology for blood flow restoration, for example for treating cerebral arteries occluded by thrombi, can often take hours to reestablish flow in the artery, and can lead to unintended complications. Apparatus and methods for treating cerebral thrombi are often ineffective or only partially effective at resolving thrombus removal, and may result in distal embolization or embolization of uninvolved arteries. For example, some current devices are designed to pierce through a thrombus, or are designed to deploy distally to the thrombus before engaging the thrombus. These devices often fail to capture all of a thrombus, can damage vessel walls distal of a thrombus, can be difficult to maneuver, can unintentionally dislodge portions of a thrombus prior to capture, and/or can take significant amounts of time to restore blood flow.
Additional treatment options include endovascular therapy and/or pharmacological agents. Pharmacological agents, specifically thrombolytics, can be used to dissolve a thrombus and restore blood flow. However, these drugs often do not work in recanalizing the vessel, may not be suitable for some patients, and may take an extended length of time to work, which can impact the cellular death distal of the thrombus. Often these drugs are used within a short treatment window, and patients late in presentation are not eligible for drug treatment. Also, these drugs can increase the risk of hemmorhage.